Aerodiesel engine

ABSTRACT

The present invention is an aero engine that is provided with compression combustion and weighs less than 725 lbs. The present invention is further a method of forming the aero engine.

RELATED APPLICATION

This application is a continuation of application Ser. No. 13/650,569filed Oct. 12, 2012, which claims the benefit of U.S. ProvisionalApplication No. 61/546,391 filed Oct. 12, 2011, each of which is herebyfully incorporated herein by reference.

FIELD OF THE INVENTION

The present invention is an aero engine useful in the fields of generalaviation and unmanned aviation. More particularly, the present inventionis a compression combustion engine adapted for use in the aviationenvironment.

BACKGROUND OF THE INVENTION

At least since WWII, light aircraft (General Aviation and, morerecently, unmanned aircraft (UAVs)) have been powered by an aircooled,gasoline fueled engine that was typically formed in an opposed sixcylinder arrangement. Such engines were fueled by very high octaneAvGas. Problematically, the non availability of AvGas in the remoteportions of the world has meant that general aviation was largelyunavailable in such areas, the very areas of the world that need generalaviation services the most. More recently it has been seen thatrefineries have been reluctant to produce AvGas, thereby stretching theworld's supply. While all fuels are not cheap, AvGas has been especiallycostly.

In contrast to the relative scarcity and costliness of AvGas, relativelyinexpensive diesel fuel and/or jet fuel (JP) is much more generallyavailable throughout the world. While the quality of such fuel can varygreatly from place to place, a compression combustion engine can burneither diesel fuel or jet fuel (JP) about equally as well. The variancescan be recognized as variance in the Cetane number (CN) of the fuel, aknowable characteristic of the fuel.

However, such a compression combustion engine presents a number ofchallenges to its designer, including:

a torque signature friendly for propeller harmonics;

fuel systems redundancy;

turbocharging design;

Bank-Bank main bearing loading; and

descent power requirements.

There is a need worldwide for an aero engine that can operate on suchfuel (diesel fuel or jet fuel (JP)), yet accounts for the challengesnoted above.

SUMMARY OF THE INVENTION

The applicant has conceived of a novel “Flat-Vee” engine to address theconcerns of the General Aviation (GA) industry in the next decades. Theengine concept utilizes novel diesel technology to enhance theefficiency of the present aircraft, and allow aircraft manufacturersaccess to emerging markets. The advantage of the Flat-Vee is that itutilizes engine architecture that makes an efficient use of material toallow the diesel to be weight competitive with present technology. Theweight of the present engine is comparable to the weight of air-cooled,opposed six cylinder engines and yet has eight cylinders and is ofcompression combustion design.

To address vibration concerns, the engine of the present invention hasutilized a “paired throw” concept that is used in conjunction with afirst order balance system to minimize vibration for aircraft structuresand passenger comfort.

The usual method that engine designers take, is to determine acrankshaft shape that works to provide the following parameters:

uniform engine firing;

satisfactory engine external balance; and

minimum bearing loads for the engine main bearings.

Although the calculations that are necessary to determine the besttrade-offs can become rather complex when multiple cylinder engines arecontemplated, the technique is well documented to determine aserviceable solution.

On a first approach the firing order of a new engine concept iscontrived with a relatively systematic approach, as noted above. Inapproaching the firing order for the present engine, several othercriteria unique to the aero environment were used to contemplatepossible firing orders, including:

a torque signature friendly for propeller harmonics;

fuel systems redundancy;

turbocharging concepts;

Bank-Bank main bearing loading; and

descent power requirements.

After considering the previous variables, a new firing order wasincorporated into the present engine that offers systems advantagesbeyond those arrived upon by the traditional techniques noted above.This firing order gives the flat-vee engine of the present inventioncapabilities that offer superior performance in the aircraft enginerole.

The engine of the present invention includes novel elements that providethe following:

1. A firing order for the paired-throw crankshaft configuration. Thefiring order (1-7-5-3-6-4-2-8), is unique for the aero engineapplication.

2. The unique firing order noted above allows the engine to be“electrically separated” in a bank-to-bank fashion for the purpose ofengine redundancy.

3. The unique firing order also allows for separate fuel systems in abank-to-bank configuration that can allow an aircraft to operate runningonly one bank (four cylinders of the eight cylinders) of the engine.

4. The firing order further allows the engine to be configured in abank-bank configuration from an air handling perspective. Turbochargerscan be configured to independently charge each engine bank, therebyallowing the engine to run on a bank-to-bank configuration in aredundant fashion.

5. The novel firing order allows the eight cylinder engine to operate asa four-cylinder engine with relatively evenly spaced firing pulses.

6. The ability to run the an eight cylinder engine in four-cylinder modeallows the injectors of the operating bank to run with an enhancedefficiency by running the firing cylinders at a higher load.

7. The new firing order does not “double fire” from a bank's perspective(that is to fire adjacent cylinders of a bank sequentially as suchadjacent firing tends to cause the oil film in the main bearings to“break down”.

8. The additional inertial and frictional load of an eight cylinderengine, as compared to the prior art six-cylinder engine, is sufficientto allow the engine to run on one bank of cylinders without causing atorsional disturbance to the propeller system.

9. One bank of the flat-vee engine can be shut down to enhance the fueleconomy of the aircraft when necessary, adding to the overall safety ofthe system.

10. Bank deactivation is also used to stabilize combustion in aircraftdescents at reduced loads, a very important consideration in UAVapplications.

11. Shared systems bank-to-bank, such as the cooling system, act as athermal battery to moderate combustion, and stabilize the engine whenonly one bank is operating.

12. The shared lubrication system allows one half of the engine tooperate with thermal stability in the event of a cooling system failure.That is, the oil system is sufficient to cool the pistons/engine whenthe heat from 4 operational cylinders is absorbed in the entire thermalmass of the engine via conduction heat transfer.

The present invention is an aero engine that is provided withcompression combustion and weighs less than 725 lbs. The presentinvention is further a method of forming the aero engine.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the engine of the present inventionmounted on a test stand and coupled to a propeller;

FIG. 2 is a front elevational schematic of the engine of claim 1;

FIG. 3 is a side elevational schematic of the engine of claim 1;

FIG. 4 is a perspective view of the crankshaft of the engine of claim 1;

FIG. 5 is a graphic representation of the inertia forces on thecrankshaft of the engine of claim 1;

FIG. 6 is a graphic representation of the nomenclature convention of theengine;

FIG. 7 is a frontal depiction of the twin turbo arrangement with abank-bank charging scheme;

FIG. 8 is a graphic depiction of hydrodynamic bearing parameters;

FIG. 9 is a graphic depiction of combined inertial and gas loading of aconrod bearing of the engine;

FIG. 10 is a graphic depiction of main bearing loadings of aconventional V-8 engine (above) and of the engine of the presentinvention (below);

FIG. 11 is a graphic depiction of engine loading when a first bank onlyis operating;

FIG. 12 is a graphic depiction of engine loading when a second bank onlyis operating;

FIG. 13 is schematic representation of the unitary coolant system flowof the present engine;

FIG. 14 is schematic representation of the unitary lubrication systemflow of the present engine; and

FIG. 15 is schematic representation of the bank-bank individuallubrication system flow of the present engine.

DETAILED DESCRIPTION OF THE DRAWINGS

The engine of the present invention is shown generally at 100 in FIGS.1-3. In an exemplary configuration, the engine 100 is operably coupledto a transfer member 104, the transfer member being operably coupled toa propeller 106. The propeller 106 has three blades 108, in thisparticular example. Other numbers of blades 108 are possible. It shouldbe noted that the engine 100 weighs no more that 725 lbs with it usualaccessories and is preferably of a 4.4 L displacement, although largeror smaller displacements may be utilized. The engine 100 develops atleast 300 hp. FIGS. 2 and 3 are schematic representations of the engine100. The engine 100 is operably coupled to a test stand 102. The engine100 is of eight cylinders in a flat opposed configuration with fourcylinders in a first bank and an opposed four cylinders in a secondbank, as noted in greater detail below.

The engine 100 of the present invention utilizes the increased cylindercount, eight, as compared to existing aero engines, six cylinders, as anapproach to minimize torque fluctuations with the intent of increasingpropeller life and decreasing the engine 100 vibrational signature. TheFlat-Vee configuration is used to primarily decrease the weight of thediesel engine by minimizing the amount of crankcase material used in itsconstruction. Additionally, the flat construction is useful in aircrafthaving multi-engine configurations, where the aerodynamic drag of theengine packages becomes more critical. A flat configuration proves to beaerodynamically advantageous where reduced drag is critical.

Many crankshaft configurations are possible in a given engine. Theforces generated by the rotating crankshaft 110 of FIG. 4 were evaluatedin the design of the engine of the present invention. As noted in FIG.5, the sum of the free forces (F_(rot), F_(I) & F_(II)) and the freemoments (M1 & M11) are independent of the firing order and interval.

The forces generated by the rotating crankshaft 110 are a function ofthe following elements of the engine design:

piston weight;

rod weight and center of gravity location Rod length versus crank throwlength;

counterweight mass;

cylinder pitch spacing; and

engine speed.

The weight of the individual engine components and the enginearchitecture was selected to control the forces generated, but thephysics of the engine train demands that the summation of forces followthe summations above, as depicted in FIG. 5.

The selected firing order has many possibilities within the crankshaftlayout of the “paired throw” scheme adopted for the present engine 100.See the crankshaft 110 of FIG. 4. As depicted in FIG. 4, the crankshaft110 has four paired throws, throw 112, throw 114, throw 116, and throw118. A pair of connecting rods for the respective pistons of twocylinders, the cylinders being on opposed banks of cylinders (describedbelow), are preferably rotatably coupled to each of the respectivepaired throws, 112, 114, 116, and 118, hence the term “paired’.

Conventions for Determination of Firing Order

The Flat Vee engine 100 includes eight cylinders that are numbered asshown in FIG. 6. The crankshaft 110 of FIG. 4 defines the y axis of FIG.6. The cylinder nomenclature convention is used in conjunction with thepaired throw crankshaft 110 as in FIG. 4. As noted in depiction for FIG.6, there are two banks of four cylinders, bank 120 and opposed bank 122.Cylinders 1-4 proceed from the rear of the engine 100 to the front, orprop side, of the engine 100. Opposed cylinders 5-8 proceed from therear of the engine 100 to the front, or prop side, of the engine 100.Cylinders 1 and 5 are rotatably coupled to paired throw 118. Cylinders 2and 6 are rotatably coupled to paired throw 116. Cylinders 3 and 7 arerotatably coupled to paired throw 114. And, cylinders 4 and 8 arerotatably coupled to paired throw 112.

Fuel Systems Redundancy

Most modern diesel engines utilize a “common rail” injection schemewhereby a high-pressure fuel pump maintains approximately 2000 bar railpressure. A rail pressure control valve maintains the rail pressure, andeach injector is fired individually by an electronic signal, the railpressure control valve and each injector being operably coupled to andcontrolled by an Engine Control Unit (ECU).

Within the confines of the above noted conventions, a configuration thatwould most appropriately fit the requirements of the general aviationapplication was determined by the applicant, keeping in mind that theengine was to be of compression combustion design. It is appreciatedthat a compression combustion design has very different considerationsfrom a gasoline fueled engine. Each of the following elements wasconsidered as the design proceeded toward its final solution for thepresent engine 100.

The present engine 100 is designed to have a higher cylinder count(eight) than current aero engines (generally six cylinders). This isdone, at least in part, because of the higher cylinder pressure of acompression combustion engine acting on the crankshaft bearing ascompared to present gasoline engines wherein combustion is initiated bya spark. An advantage of the higher cylinder count is that the inherentinertia of the additional cylinders acts to smooth the engine torque,and regulate the torque delivery.

The design of the present engine 100 does not have “double firing”,which conventionally gives a more uniform 90-degree interval over thefour-stroke cycle. Double firing is firing two cylinders, one from eachrespective bank 120, 122, simultaneously. Accordingly, over the720-degree cycle (two revolutions of the engine 100), all eightcylinders fire in 90-degree intervals.

Effective control of the vibrational level of a high-output 8-cylinderwas included in the design of engine 100 using a combination of torqueisolation elements and absorbers 124 coupled to the crankshaft 110, asdepicted in FIG. 4. Such control permitted the consideration of whatfiring order could be used to make the engine 100 redundant in a4-cylinder by 2-bank configuration. This presumption may be referred toas a 4×2 configuration for the present eight-cylinder engine 100. Such aconfiguration requires sub-dividing the engine 100 into two independentbanks 120, 122 for maximum redundancy and effectiveness.

Referring to FIG. 15, the redundant fuel injection (FI) system 130 isdepicted. In a modern common rail injection system it has beendetermined that the high-pressure fuel pump is the component mostsusceptible to failures. Accordingly, a dual pump strategy is includedin the redundant FI system 130, having two high pressure fuel pumps,132, 134. Recent advances in pump construction has lowered the combinedcomponent weight of pumps 132, 134 to within the weight range of asingle previous generation pump.

The fuel rail 136 is typically an elongate, high strength “tubemanifold” that preferably lies along each cylinder head as depicted inFIG. 15. Since the pumps 132, 134 are typically driven by a cam drivemechanism located at an end of the engine 100, it makes sense that thefuel components are integrated in a cylinder head module.

As noted in FIG. 15, fuel is drawn from a common fuel tank 138 by lowpressure pumps 140, 142, through respective fuel filters 144. Therespective engine control units (ECU) 148, 150 electronically control arespective fuel metering valve, 152, 154. It should be noted that asingle ECU may be employed as well, having the combined functions of therespective engine control units (ECU) 148, 150. Fuel is made availableby the respective fuel metering valve, 152, 154 to the respective highpressure fuel pumps, 132, 134 and thence to the respective fuelinjectors 156 of the respective banks 120 and 122.

Cylinders 1,2,3,4 are grouped in a first bank 122 and cylinders 5,6,7,8are grouped in an opposed second bank 120 as depicted in FIG. 6. Thismethod of grouping essentially electronically splits the engine 100 in a4×2 configuration that follows bank 122, 120 architecture, as describedimmediately above.

Accordingly, engine 100 is comprised of two four-cylinder engines thatshare the same crankshaft, and some other engine ancillaries, but areable to operate independently of each other. The mechanical oil andcooling systems are advantageously shared by the two four-cylinderengines, but each of the two four-cylinder engines essentially operatesindependently of the other, whether the engine 100 is operating witheight cylinders firing or with only one of the two four-cylinder enginesfiring. Preferably, a dual Engine Control Unit (ECU), performing thefunctions of ECU's 148, 150, offers near complete electrical separationof the engine 100 in a 4×2 scheme. The ECU's 148, 150 are capable ofshutting either (or both simultaneously, for that matter) of the twofour-cylinder engine banks 120, 122 down simply by stopping fuel flowthrough the respective fuel metering valve, 152, 154, or by notelectrically pulsing the corresponding injectors 156, as desired.

Turbocharging Systems Duality

The concept of 4×2 duality noted above requires duality of the aircharging system for each of the two four-cylinder engines. Mostsingle-engine installations in an aircraft utilize a tricycle gearconfiguration in which the nose gear must be integrated in the enginebay. This alone makes it desirable to integrate a twin-turboinstallation in the engine 100 in order to provide adequate space forthe wheel well necessary to stow the nose gear during nonlanding/takeoff flight configurations of the aircraft.

Additionally, since the main bearings 119 of the crankshaft 110 (seeFIG. 4) are always subjected to similar inertial loads whenever theengine 100 is turning at a given engine rpm, it must be determined whento integrate the gas forces generated by the firing of the respectivecylinders with the inertial loads. This is effected by selecting thefiring order of the engine 100. The conrod gas forces are compared tothe inertial forces in FIGS. 8 and 9. These are the same forcestransferred to the crankshaft 110 main bearings during combustion in aparticular cylinder.

FIG. 7 shows a layout that separates the air handling on a bank-bankscheme for 4×2 operation. The idea of such a scheme is to separate theair charging so that if half of the engine (for example bank 120)“quits” or is shut down, the second bank 122 does not lose its chargeair pressure by a loss of input from the non-operating bank 120. Thusthe exhaust and induction systems are separated to match the electricalredundancy put forth in the longitudinal 4×2 scheme noted above. FIG. 7depicts exhaust 170, 172 that drives the turbine portion of therespective turbos, 174, 176. The compressor portion of the respectiveturbos, 174, 176 provides charged air via the respective arrows 178, 180to respective intercoolers 182, 184. It is understood the dedicatedplumbing conveys the charged air form the respective turbos 174, 176 tothe respective intercoolers 182, 184. Intake runners 186, 188 providecharged, cooled air to the intakes of the respective banks 120, 122.Accordingly, the engine 100 is provided with redundant. independentbank-bank induction/exhaust systems.

Another advantage of such a redundant bank-bank induction/exhaust systemis discussed below in coinjunction with requirements for long descents,where it may be advantageous to “shut down” half (either bank 120 or122, as desired) of the engine 100.

Main Bearing Loading

The engine 100 is designed to avoid “dual loading” of main bearings on abank-bank basis. Inertia and cylinder pressures are typically carried byone of the 5 main bearings in any eight-cylinder, vee-engine as depictedin the upper portion of FIG. 10. Either of these forces (inertia orcylinder pressures) may load the hydrodynamic bearings (the thin film ofoil coating of a particular bearing) until the oil film is degraded to aterminal level. In practice, the crankshaft never actually “touches” itsmain bearing as it rotates due to the presence of an interposed oil filmlayer. The main bearing parameters are depicted in FIG. 8. Avoidingpaired firings on a particular paired bearing is an importantconsideration in calculating the longevity of the rotating components ofthe engine 100. The design of the present engine avoids such firings.Bearing loading of a typical prior art V type eight cylinder engine isdepicted in the upper portion of FIG. 10. Bearing loading of the engine100 is depicted in the lower portion of FIG. 10. It should be noted thatnovel firing order of the present engine 100 results in bearing loadingthat is quite similar to that of the prior art V type engine. There is,therefore, no particular load condition that that would recommend the Vconfiguration over the flat condition and vice versa.

Descent from Altitude

Aircraft encounter a reduction in the required engine power in theirdescents from altitude. The time to descent is dependent on the glideratio of a particular aircraft. Unmanned Aerial Vehicles (UAVs) aredesigned to spend as much time in theater as possible in their longmissions supporting ground-based soldiers. This feature requires thatthey use a minimum level of power to loiter and the UAV descends slowlydue to their “glider-like” flight characteristics.

Since diesel engines rely on compression ignition for combustion ratherthan spark plug ignition, the combustion resulting from compressionignition may become unstable due to the lack of control at the bottomrange of the injector operation (i.e. operation at minimum fuel usage).

Each injector in the compression combustion engine 100 is designed tohave a wide range of operation. Modern fuel injectors are designed togive multiple fuel pulses is a single injection event to shape thecombustion pressure curve of the event for low speed and low loaddriving. In many cases the common rail pressure is decreased tocompensate for the switching speed of the injector. This is at theexpense of the most efficient injector fuel atomization that occurs whenthe engine is heavily loaded. The decreased efficiency of fuelatomization typically acts to decrease engine efficiency.

The amount of power required during aircraft descents may be low enoughto warrant shutting off one of the banks 120, 122 of the engine 100.This strategy of the ECU 148 or 150 (see FIG. 15) accomplishes severaluseful things:

the strategy allows the injectors of the operating bank 120 or 122 ofcylinders to operate well within their designed range at higher fueldelivery conducive to best fuel atomization;

the frictional load of an eight cylinder engine is maintained even withone bank 120, 122 shut down, thereby allowing the engine 100 to remainthermally stable from a combustion perspective;

the fuel economy and range of the aircraft is extended during longdescents;

in situations where the fuel supply is approaching absolute minimum, thepilot has the option to extend the range of the aircraft and make a safelanding without running out of fuel; and

propeller dynamics are maintained with the appropriate firing order, bystill allowing the advantageous rate shaping of the injected fuel in theoperating bank 120 or 122 that is possible at the higher power settingof the operating four cylinder engine portion (bank 120 or 122) of theengine 100.

Details of the Firing Order

The engine 100 of the present invention employs a unique firing order,which is especially valid from a redundancy perspective in the 4×2configuration. As mentioned above, there is no clear benefit of thepresent firing order for an eight-cylinder engine from a main bearingload perspective as compared to a prior art V shape, eight cylinderengine. The advantages of the firing order adopted for the engine 100become apparent when other aspects are considered.

The adopted firing order, 1-7-5-3-6-4-2-8, of the engine 100 gives arelatively even cylinder firing when running the engine 100 as a 4cylinder engine either bank 120, 122 deactivated. Deactivation iseffected by engine control of an ECU 148, 150 on a selected bank 120 or122, as depicted in FIG. 15. The effect of relatively even firing hasthe effect of improving turbocharger performance as well and positivelyaffecting the torsional response of the engine-propeller system.

There is no “double firing” to adversely affect a paired bearing, whichfiring may break down oil films or set the engine crankshaft 110 into abending resonance.

The engine 100 can be selectively split into a 4×2 configuration thateffects a bank-bank separation. Such splitting acts to separate theengine in the manners indicated below: electrically from an enginemanagement perspective (FIG. 15);

induction from an air charging and exhaust perspective (FIG. 7); and

from a fueling perspective, when using a dual pump strategy as describedabove (FIG. 15).

Further, the shared systems help to enhance the engine 100 as a whole.The following systems are shared to enhance engine 100 function:

as depicted in FIG. 13, the cooling system is shared to act as a largethermal battery, and ensure the second bank is ready to “re-light” asdesired;

as depicted in FIG. 14, the lubrication system is shared to ensure theengine 100 does not lose its main bearing oil supply and thermalcapacity of the oil cooling system; and

the inertia of the 8-cylinder is used to moderate the torque signatureof a typical 4-cylinder engine. The added inertia still acts as a largeinherent flywheel, although 4 cylinders may not be firing. See FIGS. 11and 12 for the torque signatures of the respective banks 120, 122.

FIG. 13 is a schematic representation of the coolant system 170 of theengine 100. The coolant system 170 is single system for the engine 100without regard to the operating condition of the respective banks 120,122. Coolant is drawn from a radiator 172. The coolant is providedsimultaneously to pumps 174, 176. Pump 174 supplies coolant to bank 122and pump 176 supplies coolant to bank 120. Pump 174 pumps coolantthrough cylinder block 178, cylinder jacket 180 and cylinder head 182.Simultaneously, pump 176 pumps coolant through cylinder block 184,cylinder jacket 186 and cylinder head 188. Accordingly, under allconditions of operation, coolant is supplied to the entire engine 100.

FIG. 14 is a schematic representation of the lubrication system 190 ofthe engine 100. The lubrication system 190 is single system for theengine 100 without regard to the operating condition of the respectivebanks 120, 122. It is understood that all the rotating components of theengine 100 rotate regardless of the operating condition of the engine100. That is regardless whether the engine 100 is operating with alleight cylinders firing or whether one or the other bank 120, 122 isfiring by itself. Lubrication must therefore be provided to all therotating components of the engine 100 at all times of operation.Lubrication is drawn from an oil sump 192 by an oil pump 194. The oilpump 194 generates oil pressure in the line 196. Such pressure will openthe relief valve 198 if the pressure exceeds a certain level and willthen port oil back to the sump 192. Pressurized oil is sent past apressure sensor 200 and through a filter 202 to oil cooler 204. From theoil cooler 204, the oil is sent to the crankshaft 110 and to thecylinder heads 206, 208. After lubricating the crankshaft 110 and thecylinder heads 206, 208, low pressure oil is then sent back to the oilsump 192 via the lines 210. In accordance with the above, it is notedthat the entire engine 100 is lubricated by an integrated, common oilsystem 190 and this is the case under all operating conditions.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and will be described in detail. It should be understood,however, that the intention is not to limit the invention to theparticular embodiments described. On the contrary, the intention is tocover all modifications, equivalents, and alternatives.

1. A compression ignition engine having a flat, opposed eight cylinderarrangement, comprising: a first bank having four cylinders; a firstturbocharger coupled to an exhaust side of the first bank; a second bankhaving four cylinders, the first bank and the second bank separated by avee angle of 180 degrees; a second turbocharger coupled to an exhaustside of the second bank; and a crankshaft having four crankpins andbeing configured such that opposing pistons from the first bank and fromthe second bank are coupled to the same crankpin, wherein the fourcylinders in the first bank are numbered 1 through 4 commencing at anend of the engine and the four cylinders in the second bank are numbered5 through 8 commencing at the same end of the engine and the firingorder is 1-7-5-3-6-4-2-8, wherein the first bank and the second bank areindependently operable.
 2. The compression ignition engine of claim 1,wherein the first turbocharger is coupled to an intake side of the firstbank, and further wherein the second turbocharger is coupled to anintake side of the second bank.
 3. The compression ignition engine ofclaim 1, further comprising a first engine control unit operablyconnected to the first bank, and a second engine control unit operablyconnected to the second bank.
 4. The compression ignition engine ofclaim 1, wherein the first bank and the second bank are electricallyindependent.
 5. The compression ignition engine of claim 1, furthercomprising a first fuel control system operably connected to the firstbank, and a second fuel control system operably connected to the secondbank, the first fuel control system and the second fuel control systembeing independently operable.
 6. A method of forming an engine,including forming the engine of a flat, opposed eight cylinderarrangement with four cylinders in a first bank and four cylinders in anopposed second bank, the first bank and the second bank separated by avee angle of 180 degrees, the engine including: a first turbochargercoupled to an exhaust side of the first bank; a second turbochargercoupled to an exhaust side of the second bank; and a crankshaft havingfour crankpins and being configured such that opposing pistons from eachbank are coupled to the same crankpin, and numbering the four cylindersin the first bank 1 through 4 commencing at an end of the engine andnumbering the four cylinders in the second bank 5 through 8 commencingat the same end of the engine and establishing a firing order as1-7-5-3-6-4-2-8, wherein the first bank and the second bank areindependently operable.
 7. The method of forming the engine of claim 6,wherein the first turbocharger is coupled to an intake side of the firstbank, and further wherein the second turbocharger is coupled to anintake side of the second bank.
 8. The method of forming the engine ofclaim 6, further comprising: providing a first engine control unitoperably connected to the first bank; and providing a second enginecontrol unit operably connected to the second bank.
 9. The method offorming the engine of claim 6, wherein the first bank and the secondbank are electrically independent.
 10. The method of forming the engineof claim 6, further comprising: providing a first fuel control systemoperably connected to the first bank; and providing a second fuelcontrol system operably connected to the second bank, the first fuelcontrol system and the second fuel control system being independentlyoperable.
 11. An engine, comprising: a first bank of four cylindersnumbered 1 through 4 commencing at an end of the engine, each cylinderconfigured to receive a piston; a first turbocharger coupled to anexhaust side of the first bank; a second bank of four cylinders numbered5 through 8 commencing at the same end of the engine, each cylinderconfigured to receive a piston; a second turbocharger coupled to anexhaust side of the second bank; and a crankshaft, having four crankpinsand being configured such that opposing pistons from the first bank andfrom the second bank are coupled to the same crankpin, wherein the firstbank of cylinders and the second bank of cylinders are separated by avee angle of 180 degrees and further wherein the engine has a firingorder as 1-7-5-3-6-4-2-8, and further wherein the first bank and thesecond bank are independently operable.
 12. The engine of claim 11,wherein the first turbocharger is coupled to an intake side of the firstbank, and further wherein the second turbocharger is coupled to anintake side of the second bank.
 13. The engine of claim 11, furthercomprising a first engine control unit operably connected to the firstbank, and a second engine control unit operably connected to the secondbank.
 14. The engine of claim 11, wherein the first bank and the secondbank are electrically independent.
 15. The engine of claim 11, furthercomprising a first fuel control system operably connected to the firstbank, and a second fuel control system operably connected to the secondbank, the first fuel control system and the second fuel control systembeing independently operable.